The Treasury of Atreus is one of the most important monuments of the Bronze Age in Greece and is universally recognized as the supreme example of Mycenaean architecture. It is also the finest of all the many beehive or tholos tombs which are such a striking feature of Mycenaean culture. The beehive-tomb is essentially a creation of the architecture of the Greek mainland and of Mycenaean as opposed to Minoan building. In Crete so far three beehive-tombs of Bronze Age date are known, two of which—one at Hagios Theodoros and another just found at Knossos—date from late L.M. III, the very end of the Bronze Age. The third, found at Knossos in 1938, is not to be dated earlier than 1500 B.C. All three are small and poorly constructed. The Early Bronze Age circular ossuaries of Mesarà in Crete, often erroneously described as beehive-tombs, are, as Professor Marinatos has provel nothing of the kind. On the other hand, on the Greek Mainland and in the islands immediately adjacent to it, at least forty beehive-tombs are so far known. These figures are enough to indicate that the beehivetomb is a product of Mainland or Mycenaean rather than of Cretan or Minoan architecture. More accurate information about the date and construction of the Treasury of Atreus, the finest of all the beehivetombs, cannot fail to enlarge our knowledge of the history and art of the Mycenaean civilization.